It is proposed to further elucidate the mechanisms of action of proteolytic enzymes. The principal enzymes to be investigated include chymotrypsin, because of its ready availability and wealth of background information, and the enzyme elastase, because of its easy crystallizability. With all enzymes it is hoped to specify all intermediates and to determine the specificity of all steps. With chymotrypsin a considerable amount of stopped-flow kinetics is contemplated (in the millisecond time range). The investigation chymotrypsin attached covalently to a solid support is also proposed. The enzyme elastase will be compared to other proteolytic enzymes in an effort to elucidate its mechanism. The mechanism of action of the proteolytic enzyme concerned with cancerous cells will be investigated. Bibliographic referencs: E. J. Breaux and Myron L. Bender, "The Binding of Specific and Non-specific Aldehyde Substrate Analogs to alpha-Chymotrypsin", FEBS Letters, 56, 81-84 (1975). Joseph W. Amshey, Jr. Satya P. Jindal and Myron L. Bender, "The Deacylation of Substituted Benzoyl-alpha-Chymotrypsins", Arch. Biochem. Biophys., 169, 1-6 (1975).